‘Invisible’ integrated standing seam solar roof gains traction among UK architects with its capacity to generate four times the energy its home consumes
A fully-integrated solar roof, installed on the UK’s first Passivhaus Premium-certified home and able to generate more than four times the energy than the house consumes, has been specified on four other newbuild and extension projects.
The 2-in-1 roofing panel, Velario, combines a steel standing seam with PERC photovoltaic cells fused to the surface. It is manufactured by Estonia-based Roofit.Solar and distributed in England and Wales by Future Tech Solar.
The system installed on the 4-bed Passivhaus Premium property in the north Cotswolds featured on a recent episode of Channel 4’s Grand Designs and since it aired Velario has been specified on three other residential projects and one building in a castle estate, all due to start on site in late January/early February 2025.
Gerry Smyth from UK distributor Future Tech Solar said: ‘Each project has gone through a rigorous process with planning whereby the architects had to consult on a “material change” of roofing product and, furthermore, they got Roofit.Solar specified as the roofing solution.’
Velario roof panels come in 115W, 145W, and 175W versions and are designed for sloped roofs with a minimum pitch of 10°. The monocrystalline solar cells deliver a power output of 160 W/m² and work even in low-light conditions.
Smyth explains that custom software calculates the best configuration for each roof based on the architect’s plans. The system is installed by contractors in the same process as a traditional double metal seam roof, using a timber batton structure to apply the metal to.
Panels cover most of the surface, ‘apart from about a foot either side’, says Smyth, with a standard metal seam required for ‘any hips or gullies, or, for example, around Velux roof lights.’
The SSAB steel panels, manufactured by Roofit.Solar’s partner Ruukki, are sealed with a layer of organic GreenCoat designed to withstand harsh weather conditions.
The north Cotswolds roofing project cost £120,000 to cover one third of the 600m2 roof with Velario. This covered the entire solar installation, including batteries, inverters, and MCS-certified panels.
The owner exported 40MW hours of electricity back to the grid in the first year, although he said the process hit hurdles due to issues with current grid infrastructure. The house generates more power than the current cap on the amount of electricity that can be sold back to the grid.
To achieve Passivhaus Premium certification a building must generate over 120 kWh/m² of renewable energy while consuming less than 30 kWh/m².